Multiscale photonic imaging of the native and implanted cochlea

The cochlea of our auditory system is an intricate structure deeply embedded in the temporal bone. Compared with other sensory organs such as the eye, the cochlea has remained poorly accessible for investigation, for example, by imaging. This limitation also concerns the further development of technology for restoring hearing in the case of cochlear dysfunction, which requires quantitative information on spatial dimensions and the sensorineural status of the cochlea. Here, we employed X-ray phase-contrast tomography and light-sheet fluorescence microscopy and their combination for multiscale and multimodal imaging of cochlear morphology in species that serve as established animal models for auditory research. We provide a systematic reference for morphological parameters relevant for cochlear implant development for rodent and nonhuman primate models. We simulate the spread of light from the emitters of the optical implants within the reconstructed nonhuman primate cochlea, which indicates a spatially narrow optogenetic excitation of spiral ganglion neurons.

Automated summary

The cochlea, as a complex structure deeply embedded in the temporal bone, has been difficult to investigate using traditional imaging methods. In order to develop technology for restoring hearing, quantitative information on cochlear dimensions and sensorineural status is crucial. By employing X-ray phase-contrast tomography and light-sheet fluorescence microscopy, researchers provided a systematic reference for designing cochlear implants for rodent and nonhuman primate models. Simulation showed a spatially narrow optogenetic excitation of spiral ganglion neurons in reconstructed nonhuman primate cochleas.